Insulator



Sept. 11, 1928.

W. H. SCHRAMM INSULATOR Filed llafch 10, 192'! wiTNEssEs: v INVENTOR Wa/ferhf Sc/rmmm Patented Sept. 11,, 1928.

UNITE-D. s rares PATENT oFncE- WALTER H. SCHRAII, OI PITTSBURGH, PENNSYLVANIA, ASSIGNO R '10 WESTING- HOUSE ELECTRIC a MANUFACTURING COMPANY, A CQBPOBATION OF PENNSYL- vama.

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Application and um 10, 1927. Serial 1%. 174,1:1.

My invention relates toinsulatorsand particularly to insulators that are subject to cantilever loads. A

One object of my invention is to provide an insulator, of the above-indicated character,

that shall be reinforced against fracture at a position in which breakage normally occurs under a cantilever load.

Another object of my invention is to provide means for materially strengthening. an insulator against a cantilever load without impairing the insulating character of the insulator.- 1

Another object of my invention is to provide insulating means for increasing the mechanical. strength of an insulator of .a given size without increasing the dimensions of the insulator.

A further object of my invention is to pro-- vide aninsulator, that shall be simple and durable in construction, economical to manufacture-and-efiective in its operation.

In insulators for supporting cantilever loads, such as those'for supporting bus-bars and the like, the main insulating bodies are subject to breakage, near the base ends thereof, beyond the outer ends of the 'usual metal collars or supporting members which surround the bodies. To reinforce the insulators against such breakage, it has heretofore been suggested to place metal membersinside thebase ends of the insulators. These inserts however, materially modify, or interfere with, the original-insulating characteristics of the insulators. I

' When the above-mentioned Inetal'inserts are not employed, it has been suggested to construct theinsulators lar er than the electrical requirements theme in an endeavor to obtain greater mechanical strength.

However, in tests wh'ch I have conducted, ithas been found that, in certam'instances,

increasingthe size of the insulator does not 1 provide the desired strength. For instance,

it has been found that a cylindrical-insulating member of a-certain type, eight inches indiameter is not appreciably stronger'than a six inch insulator 'of'the same type.

later that will be su jectedto cantilever load in use; but that shall he no largerthan necessary for effective mechanical operation and aimto provide an insu-' that shall, b the absence of the abovementioned meta insert member, be more effective electrically than an insulator in whichv such an insert is employed.

Accordingly, in practicing my invention,

'1 provide an insulator subject to cantilever load that is so reinforced by insulating means, in the form of insulating laminae or layers,

across the line or zohe of normal load frac-- ture, as to greatly strengthen the insulator,

my invention. I I v The nsulator comprises, in general, a main lnsula-tmg body portion or member 2, an outer-end member 3 fon supporting a bus-bar or 1 other conductor (not shown), a main supporting or base member'4 and a reinforcing element 5 constituting a portion ,of my invention;

The insulating body p0rtion2, preferably of porcelain or glass, is of substantiallyhoL low cylindrical shape having outer surfacecreepage corrugations or flanges 7 and an intermedlate wall or web portion 8 which functions as an electrical barrier, as a cross brace against cantilever load and, also, to provide separate outer and base-end recesses or cup portions for the reception of the members 3 and 5, respectively.

The member 3, preferably constructed .of metal, comprises an outer flange portion 10,

disposed against the outer-end surface of the insulating body 2, and a cup portion- 11 closely conforming to the outer recess in the body and secured thereto by, a body 12 of bonding material, such as cement, composition, or the'like. An opening 14 in the flange 10 rovides shoulders 15 to which elements not shown) may be anchored or secured for holding a conductor or bus-bar in position.

The base member 4, preferably of metal, comprises a cylindrical. collar or sleeve portion 17 surrounding, and bonded to, the base end of the'insulating body 2 and ad'aterally projecting annular flange 18 having openings 1 19 for'the reception of screws or boltsby which the insulator is" mounted in position I preferably of'the same mate- The member 5,

rial as the insu ating bodymember 2,, is of inverted substantially cup-shape having sidewall rtions'21closely conforming, and 'dispose in slightly spaced, relation, to the inner longitudinal side surfaces of the base-end recess of the body 2. The closed-end wall 22 of the cup 5 is preferably of substantially flat discoidal form disposed substantially parallel to the adjacent surface of the web 8 and to a normal fracture zone across the body 2, as represented by a line XX. A body of bonding material 23, such as cement, or the like, is placed in a preferably uniform layer between the outer surfaceof the cup 5 and the adjacent surfaces ofthe body 2. The

cemented surfaces may be sanded or otherwise treated to ensure a more perfect bond with the cement or other bonding material.

In the above-described structure, the web a 8 and the wall 22 of the cup 5 constitute cross braces against thecantilever load. The inner-end side walls, together with the side walls 21 of the cup 5, constitute a laminated insulating structure which traverses the zone XX of normal load fracture. Since 1aminated structures are stronger than solid structures of the same material and the cement body 23 is also usually as strong as, or

' stronger than, the refractory bodies 2 and 5,

ticular form of my invention, changes may;

be effected therein without departing from the spirit and scope thereof, as indicated by the appended claims. I

I claim as my invention:

1. An insulator subject to cantilever load comprising an insulating member having a cupped base end and means for reinforcing the same against normal load fracture into said end with its closed end adjacent to the bottom of said recess.

3. An insulator comprising a cylindrical insulating member subject to cantilever load and having a cupped base end, a metal supporting member therefor having a cylindrical portion surrounding the base end thereof and an insulating cup substantially conforming to the recess in'said end and bonded to said end with its closed end adjacent to the bottom of said recess.

4. An insulator comprising a cylindrical insulating member subject to cantilever'load and having a recessed base end, a metal supporting member therefor having a cylindrical portion surrounding said end, the arrangement of parts normally creating a loadfracture zone across, and adjacent to the outer end of, said metal cylindrical portion and an insulating cup in said recess having its closed end substantially parallel, and adjacent, to said zone.

5 An insulator comprising a hollow cylindrical insulating member subject to cantilever load, a metal supporting member therefor having a cylindrical portion-surrounding the base end thereof, said insulating member having a transverse web portion across the hollow portion thereof outwardly beyond the outer end of said metal cylindrical portion and an insulating cup bonded in position in said base end having sides closely conforming to the 'inner side surface of the insulating member and an end wall parallel, and adjacent to, said web portion. 7

' In testimony whereof, I have hereunto subscri jaed my name this first day of March, 192

WALTER H. SCHRAMM. 

